Add MerkleInstructions

src/circuit/gadget.rs

@@ -1,3 +1,4 @@
 pub(crate) mod ecc;
+pub(crate) mod orchard_action;
 pub(crate) mod sinsemilla;
 pub(crate) mod utilities;

src/circuit/gadget/orchard_action.rs

@@ -0,0 +1 @@
+mod merkle;

src/circuit/gadget/orchard_action/merkle.rs

@@ -0,0 +1,115 @@
+use halo2::{
+    circuit::{Cell, Chip, Layouter, Region},
+    plonk::{Advice, Column, ConstraintSystem, Error, Permutation},
+};
+use pasta_curves::arithmetic::{CurveAffine, FieldExt};
+use std::marker::PhantomData;
+
+use crate::circuit::gadget::{
+    ecc::{
+        chip::{EccChip, EccConfig},
+        EccInstructions,
+    },
+    sinsemilla::{SinsemillaChip, SinsemillaConfig, SinsemillaInstructions},
+    utilities::{UtilitiesChip, UtilitiesConfig, UtilitiesInstructions, Var},
+};
+use std::convert::TryInto;
+
+enum Node<F: FieldExt> {
+    Leaf(Var<F>),
+    Inner(Var<F>),
+    Sibling(Var<F>),
+}
+struct Root<F: FieldExt>(pub Var<F>);
+
+pub trait MerkleInstructions<F: FieldExt, const MERKLE_DEPTH: usize>:
+    UtilitiesInstructions<F>
+{
+    /// Check the validity of a Merkle path from a given leaf to a claimed root.
+    fn merkle_path_check(
+        &self,
+        layouter: impl Layouter<F>,
+        root: Option<[u8; 32]>,
+        leaf: Option<[u8; 32]>,
+        merkle_path: [Option<[u8; 32]>; MERKLE_DEPTH],
+    ) -> Result<(), Error> {
+        Ok(())
+    }
+}
+
+fn layer_hash<C: CurveAffine>(
+    chip: MerkleChip<C>,
+    layer: u16,
+    left: Node<C::Base>,
+    right: Node<C::Base>,
+) -> Result<Var<C::Base>, Error> {
+    todo!()
+}
+
+#[derive(Clone, Debug)]
+pub struct MerkleConfig {
+    config1: (UtilitiesConfig, SinsemillaConfig),
+    config2: (UtilitiesConfig, SinsemillaConfig),
+}
+
+pub struct MerkleChip<C: CurveAffine> {
+    config: MerkleConfig,
+    _marker: PhantomData<C>,
+}
+
+impl<C: CurveAffine> Chip<C::Base> for MerkleChip<C> {
+    type Config = MerkleConfig;
+    type Loaded = ();
+
+    fn config(&self) -> &Self::Config {
+        &self.config
+    }
+
+    fn loaded(&self) -> &Self::Loaded {
+        &()
+    }
+}
+
+impl<C: CurveAffine> MerkleChip<C> {
+    pub fn configure(
+        meta: &mut ConstraintSystem<C::Base>,
+        advices: [Column<Advice>; 10],
+        perm: Permutation,
+    ) -> MerkleConfig {
+        let ecc_config = EccChip::<C>::configure(meta, advices);
+
+        let lookup = (
+            meta.fixed_column(),
+            meta.fixed_column(),
+            meta.fixed_column(),
+        );
+        let config1 = (
+            UtilitiesChip::configure(meta, advices.clone()[..5].try_into().unwrap(), perm.clone()),
+            SinsemillaChip::<C>::configure(
+                meta,
+                ecc_config.clone(),
+                advices.clone()[..5].try_into().unwrap(),
+                lookup,
+                perm.clone(),
+            ),
+        );
+        let config2 = (
+            UtilitiesChip::configure(meta, advices.clone()[5..].try_into().unwrap(), perm.clone()),
+            SinsemillaChip::<C>::configure(
+                meta,
+                ecc_config,
+                advices.clone()[5..].try_into().unwrap(),
+                lookup,
+                perm.clone(),
+            ),
+        );
+        MerkleConfig { config1, config2 }
+    }
+
+    pub fn construct(config: MerkleConfig) -> Self {
+        MerkleChip {
+            config,
+            _marker: PhantomData,
+        }
+    }
+}

src/circuit/gadget/utilities.rs

@@ -5,8 +5,8 @@ use halo2::{
 use pasta_curves::arithmetic::FieldExt;
 use std::marker::PhantomData;
 
-mod cond_swap;
-mod plonk;
+pub mod cond_swap;
+pub mod plonk;
 
 use cond_swap::{CondSwapChip, CondSwapConfig, CondSwapInstructions, Pair, Swap};
 use plonk::{PLONKChip, PLONKConfig, PLONKInstructions};
@@ -19,7 +19,7 @@ pub struct Var<F: FieldExt> {
 }
 
 #[derive(Clone, Debug)]
-struct UtilitiesConfig {
+pub struct UtilitiesConfig {
     // Column where private inputs are witnessed.
     private: Column<Advice>,
     // Config to use a conditional swap chip.
@@ -28,7 +28,7 @@ struct UtilitiesConfig {
     plonk_config: PLONKConfig,
 }
 
-struct UtilitiesChip<F: FieldExt> {
+pub struct UtilitiesChip<F: FieldExt> {
     config: UtilitiesConfig,
     _marker: PhantomData<F>,
 }
@@ -70,7 +70,7 @@ impl<F: FieldExt> UtilitiesChip<F> {
     }
 }
 
-trait UtilitiesInstructions<F: FieldExt>: CondSwapInstructions<F> {
+pub trait UtilitiesInstructions<F: FieldExt>: CondSwapInstructions<F> {
     type Var;
 
     /// Load a private input into the circuit.

src/constants.rs

@@ -18,6 +18,9 @@ pub mod util;
 
 pub use load::{OrchardFixedBase, OrchardFixedBasesFull, ValueCommitV};
 
+/// $\mathsf{MerkleDepth^{Orchard}}$
+pub(crate) const MERKLE_DEPTH_ORCHARD: usize = 32;
+
 /// $\ell^\mathsf{Orchard}_\mathsf{base}$
 pub(crate) const L_ORCHARD_BASE: usize = 255;